With the continuing development of scientific technology, the face detection function has been added to more and more electronic products. For example, with the face detection function added to his smartphone, a user can make use of the function to unlock the smartphone. As such, the user's safe use of his smartphone is greatly ensured and the user's sensory experience is significantly improved.
According to one technique, in order to achieve the above effect, the smartphone is provided with a front camera which is connected to the smartphone's processor through a Mobile Industry Processor Interface (MIPI) architecture. In a specific implementation, the user firstly operates the smartphone to light its screen; after that, the user activates the face detection function of the smartphone; then, the front camera collects the current image and transmits the current image to the processor through the MIPI architecture; when the processor determines that a face exists in the current image, it controls the smartphone to release the current locked state. Thus, according to the technique, in order to control the smartphone in real time to release the current locked state by performing face detection, the front camera and the processor have to be constantly in an operating state and the MIPI architecture has to be used.
Existing focusing methods are grouped into two major classifications: one is active focusing; and the other is passive focusing. The active focusing was mainly used in legacy cameras, while the passive focusing (also known as auto-focusing) is now used in handsets, tablet computers and cameras. Typically, when a collected preview image contains a face, the electronic device will automatically recognize the face on the preview image and then place the focal plane on the face plane to complete the auto-focusing.
When implementing technical solutions according to embodiments of the disclosure, the inventors of the application find that the following technical problems exist in the prior art:
In order to control the smartphone to release the current locked state by performing face detection in real time, the smartphone has to keep the front camera and the processor operating and has to use the MIPI architecture. Because the front camera, the image processor and the MIPI architecture consume a large amount of power when operating, the overall power consumption of the smartphone is high.
In addition, there is a technical problem that, when the front camera collects the current image by performing focusing, the focusing process is slow and takes a long time.